1. Field of the Invention
This invention relates to a lamp support for supporting films, specifically to a backlight module whose friction with the light diffusion film is reduced.
2. Description of the Prior Art
When liquid crystal display technology is applied in large displays such as liquid crystal televisions and billboards, optical sheets such as light diffusion films and prism plates may deform and cause change in size due to thermal expansions and contractions. The deformations of optical sheets may cause visible effect on the optical characteristics of large displays. Therefore, in order to solve the problem mentioned above, several conventional backlight modules are provided in the market to support the optical sheets and limit the deformation (e.g. warpage) of the optical sheets.
As FIG. 1A shows, a conventional supporting element 12 is disposed on a base 14 and two ends of the base 14 are disposed with positioning units 16. A light diffusion film is normally disposed above the conventional supporting element 12 and covered with a frame (not illustrated). During backlight module assembly and follow-up tests such as reliability tests, the conventional supporting element 12 used to support optical sheets such as light diffusion film may rub against the light diffusion film and may damage or even destroy the light diffusion film. The damage or destruction to the light diffusion film may necessitate the replacement of the film, further increasing the costs in production.
FIG. 1B is another schematic view of a conventional backlight device. As FIG. 1B shows, the conventional supporting element 12 is an elastic cone to prevent deformation in the light diffusion film 30. The conventional supporting element 12 further includes an elastic element 22 covered with a restraining element 24 and the bottom of a cone is connected to the elastic element 22 so that the cone can vibrate with respect to the restraining element 24. A plurality of lamps 20 are disposed at two sides of the supporting element 12 and covered by the frame 50. As FIG. 1B shows, although the deformation of the light diffusion film 30 is buffered by the up-down movable cone, there is still a significant chance for the cone and the light diffusion film 30 to rub against each other.
FIG. 1C is a schematic view of yet another backlight module. The conventional supporting element 12 is disposed between the light diffusion film 30 and a light reflector 40 whereas the light diffusion film 30 is disposed on top of the conventional supporting 12. In the present embodiment of the conventional backlight module, a buffer 18 is connected to both the bottom of the conventional supporting element 12 and the light reflector 40. In this way, the buffer 18 allows the conventional supporting element 12 to shake and absorb vibrations or other forces to reduce the friction between the conventional supporting element 12 and the light diffusion film 30. However, the supporting element 12 and the light diffusion film 30 mentioned above can still rub against each other to create scrapes and annoying sound.
Thus, it is desired to provide a backlight module capable of improving the problems mentioned above.